Shaving head for an electric shaver



Sept. 17, 1968 J. GODEFROY SHAVING HEAD FOR AN ELECTRIC SHAVER Filed May5, 1967 2 Sheets-Sheet 1 rlll/r/lllllllrlllllll INVENTOR w/a/m x 6'0 defr y BY WM ATTORNEYS J. GODEFROY SHAVING HEAD FOR AN ELECTRIC SHAVER vSept. 17, 1968 Filed May 5, 1967 FIG.2

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I INVENTOR Jo m7? 6a defr y BY I ATTORNEYS United States Patent O3,401,454 SHAVING HEAD FOR AN ELECTRIC SHAVER Johan Godefroy, Overveen,Bloemeudaal, Netherlands, assiguor to Inventa Trust reg., Vaduz,Liechtenstein Filed May 5, 1967, Ser. No. 636,383 Claims priority,application Netherlands, Oct. 27, 1966, 661 193 2 Claims. (Cl. 3043.91)

ABSTRACT OF THE DISCLOSURE An electric shaver having a cutter headvibrational in its longitudinal direction and urged by'springs against ashaving plate clamped on a frame which may perform a rocking movementabout an axis extending parallel to the longitudinal axis of the cutterhead, the frequency of the longitudinal movement of the cutter headbeing a muliple of the frequency of the rocking movement of the shavingplate, the cutter head participating in the rocking movement of theshaving plate; the coupling between the cutter head and the driving partcoupled with the motor allowing a mutual movement of said partstransversely to the direction of the cutter head.

This invention relates to a shaving head for an electric shaver,comprising a cutter head movable in longitudinal direction with mainlysemi-circular cutter blades which are pressed by springs against theinner surface of a shaving plate provided with shaving apertures andclamped on a frame, said frame being adapted to perform a rockingmovement about an axis extending parallel to the longitudinal axis,which is effected by the same motor which is used to cause alongitudinal vibration movement of the cutter head, the frequency ofsaid vibration movement being a multiple of the frequency of the rockingmovement of the shaving plate.

In this known shaving head a suitable selection of the location of therocking axis renders it possible that at various points of thecircumference of the shaving head the moving parts of the shaving platedirected according to the radius and the tangent have a differentrelation so that by gradually changing the position of the shaverrelative to the skin the most effective point may be found.

A drawback of this construction is that during the rocking movement theinner surface of the shaving plate also moves transversely to thelongitudinal axis relative to the cutter blades, While, moreover,between the shaving plate and the cutter head considerable transverseforces of continually varying magnitude occur, the fric- 'tion as wellas the transverse forces being unequally distributed along thecircumference of the shaving plate. This varying and irregular load ofthe shaving plate and the cutter head will result in fatigue and a rapidwear of this shaving plate and cutter head.

The invention aims at providing a shaving head of the afore-mentionedkind which does not present these drawbacks. For this purpose saidshaving head is characterized in that the cutter head is supported bythe frame of the shaving plate for longitudinal movement, thecornpression springs forthe cutter head also acting on said frame'sothat the cutter head may participate in the rocking movement of theshaving plate, and in that'the coupling between the cutter head and thedriving part coupled with the motor allows a mutual movement of saidparts transversely to the direction of vibration of the cutter head.

In this way it is accomplished that the only mutual movement between thecutter head and the shaving plate is the longitudinal vibration movementof the cutter head, and that the load of the shaving plate and theblades, at least in circumferential direction, is mainly constant anduniform. In particular it is possible for the cutter head to bepivotally connected by means of bearing pins to the frame of the shavingplate at or near a longitudinal side by means of bearing pins; thecompression springs acting at or near the other longitudinal side of thecutter head.

In particular, the rocking axis of the shaving head is situated sidewaysof the longitudinal centre plane of the shaving head, the bearing pinsof the cutter head being arranged on the other side of said centreplane. The result is that the shaving plate performs near said bearingpins, where the plate is hardly yieldingly supported by the cutter head,a movement directed mainly transversely to the surface, whereas near therocking axis, where mainly a movement parallel to the surface is carriedout, said plate is yieldingly supported.

It is furthermore advisable to arrange .the oblong shaving apertures ofthe shaving plate in rows extending perpendicular to the axis of theshaving head, and also to arrange the cutter blades of the cutter headobliquely relative to said axis.

If the shaver comprises a rotating motor the driving shaft of whichextends perpendicular to the longitudinal axis of the shaving head andwhich by way of a crank drive or the like is coupled with the cutterhead, the crank with the engaging coupling sleeve of the cutter head isconstructed such that the crank is movable transversely to the axis ofvibration in said sleeve.

The invention will be further explained below with reference to theaccompanying drawings; these drawings show in:

FIG. 1 a cross-section of a shaving head according to the inventiontaken along the line II of FIG. 2 with exploded parts;

FIG. 2 a partial longitudinal section, mainly taken according to theline IIII of FIG. 1, in assembled condition; and

FIG. 3 a top plan view of a preferred embodiment of the shaving headaccording to the invention with broken-away portions.

On a base plate 1, with which the shaving head is secured on the shaver,there are provided two lateral supports 2. In said lateral supportsthere are mounted pivot pins 3 arranged in line with each other, thecommon axis of said pivot pins extending parallel to the longitudinalaxis of the shaving head and mostly at some distance thereof as shown inthe drawings. These pins 3 serve as fulcrums for the shaving head properwhich consists of a frame 4, a cutter head 5 situtated within saidframe, and a shaving plate 6 clamped on the frame and provided in theusual way with shaving slots or shaving apertures 7. The frame 4comprises two end pieces 8 in which bearing bushings 9 are provided, thepins 3 fitting into these bushings. The cutter head 5 is provided with aplurality of cutter blades 10, the circumference of which lies againstthe inner surface of the shaving plate 6.

In each end piece 8 there is furthermore provided near the circumferencean inwardly projecting bearing pin 11, said pins being arranged in linewith each other.

These pins have been inserted into bearing bushes 12 of the cutter headwhich thus is rotatable and is supported somewhat slidably inlongitudinal direction. At the other side a number of compressionsprings 13 are provided which press the cutter head against the shavingplate 6.

At the bottom side of the frame 4 there is secured a fork 14 grippingaround a crank pin 15 or the like. This crank is driven through theintermediary of a worm gear reducer 16 by the shaft 17 of the motor ofthe shaver. Upon rotation of the motor the fork 14 is given atransversal reciprocating movement so that consequently the shaving headperforms a periodic tilting movement about the shaft of the pins 3. Atthe upper end of the shaft 17 a crank pin 18 or the like is providedwhich fits in an adapted cross slot 19 of the cutter head 5. Uponrotation of the motor a longitudinal vibration is thus imparted to thecutter head, the cutter blades sliding past the slots 7 and cutting offthe beard hairs projecting through said slots.

Since the cutter head 5 is supported by the frame 4 this head togetherwith the frame performs a rocking movement so that the only mutualmovement which these parts perform relative to each other is thelongitudinal vibration movement of the cutter head which only has a verysmall length of stroke. In order to render this comon rocking movementpossible the transverse slot 19which may be provided with a suitablebearing bushing 20must be shaped such that a roller arranged on crankpin 18 has sufficient clearance in the direction of the shaft.

As shown in the drawings the shaft of the pivot pins 3 is situated onone side and the shaft of the bearing pins 11 on the other side of thelongitudinal center plane of the head. The consequence thereof is thatthe movement of the shaving plate near a line connecting the centerlines of bearing pins 11 comprises a relatively large componentperpendicular to and a small component parallel to the surface. On theother hand the plate performs near a line connecting the center lines ofpivot pins 3 practically only a parallel movement with a small length ofstroke, and near the springs 13 a small perpendicular component is againadded thereto.

In the portion near the line connecting the center lines of bearing pins11 the shaving plate is hardly yieldingly supported against transverseforces on account of the proximity of this axis, whereas this supportnear the axis yields so that in that region the shaving plate can besomewhat depressed. The various distributions of velocity and supportsare now made use of in the following manner.

Skin portions supported by jaw-bones will in general be shaved best withthe aid of that part of the shaving plate which is situated near theline connecting the center lines of bearing pins 3. The shaving platecan yield somewhat and fit itself to the slightly yielding skin surface,and in consequence of the small parallel movement of the shaving platethe skin is stretched and at the same time flattened hairs get theopportunity to stand up in the apertures of the shaving plate.

Non-supported skin portions, such as of the cheeks and the throat, aremuch more diflicult to shave, since in consequence of the yieldingproperty of the skin the hairs are not pressed outwards so that smoothshaving is rendered difficult. While the skin on the cheeks is stillsupported by relatively firm muscular tissue, this is not the case withthe skin of the throat so that the latter is much more flaccid, and maypenetrate into the openings of the shaving plate which may give rise toinjuries. When the shaving head performs a periodic movementperpendicular to the skin and with such velocity that a local depressionof the skin is not restored as a result of the inertia before the nextstroke of the shaving plate arrives, the hairs in a yielding skinportion are erected and pressed outwards as a result of the skin beingstretched.

The shaving plate portion near the line connecting the center lines ofbearing pins 11 which performs the largest transverse movement, ispreeminently suitable for shaving the cheeks, whereas for shaving thethroat depending on the sensitiveness of the skin a shaving plateportion of smaller transverse movement may be selected, which is locatedbetween the line connecting the center lines of bearing pins 11 and theline connecting the center lines of bearing pins 3 or close to thesprings 13.

As is apparent from the preceding lines these various movements arecarried out by the various shaving plate portions so that by directingthe shaver or by turning it a shaving action adapted to the skin surfacecan always be obtained.

If the shaving plate comprises rectangular apertures the latter mustextend obliquely relative to the blades in order to obtain a shearingaction as well as to prevent the edges of the blades from strikingagainst a straight edge of these apertures and thus being damaged. Inthe usual shavers the blades are arranged transversely to thelongitudinal edges of the shaving head, the apertures being arranged inrows extending obliquely relative to said longitudinal axis. In the caseof a rocking head ac cording to the invention, however, such obliquelyarranged apertures are less favourable, since especially in those partswhere the component of movement parallel to the shaving plate surface islarge the hairs situated opposite an aperture may be flattened duringthe rocking movement by a dam between the apertures. It is therefore tobe preferred to have the rows of the apertures extend transversely tothe longitudinal axis of the shaving head so that then the blades of thecutter head must be arranged at an angle relative to said axis.

It is furthermore necessary to cover the ends of the shaving plate toprevent injuries. For this purpose an end cap 21 is provided at each endof the shaving head. These end caps cover the end portions of theshaving plate with sufficient clearance thus preventing the occurence offriction between the end caps and the end portions.

In order to be able to clean the shaving unit easily it is preferable toclamp the shaving plate on an auxiliary cage 22 on which also the endcaps 21 are secured and which are connected with the frame 4 at least ina partly detachable manner by means of a pivot or a snap lock 23 on oneside and a snap lock on the other side.

From the preceding description it clearly appears that the shaving headaccording to the invention constitutes an independent unit which simplymay be removed from the shaver and replaced by another one. This unitmay be fastened on the mantle of the shaver for example by a simple snaplock. Furthermore this shaving head comprises only a small number ofparts which can be assembled and taken to pieces in a simple manner.

Iclaim:

1. A shaving head for an electric shaver having a housing and a motor,said head comprising a frame mounted for rocking movement with respectto said housing; means operatively connecting said frame and said motorto effect said rocking movement; a shaving plate removably fixed on saidframe; a cutter head having a plurality of substantially semi-circularblades mounted within said frame for longitudinal movement with respectto said plate; means pivotally connecting said cutter head to saidframe, said latter connection being near one longitudinal side of saidcutter head; resilient means disposed between the other longitudinalside of said cutter head and said frame to urge said blades against saidplate; and means operatively connecting said motor and said cutter headto cause longitudinal vibration of said cutter head with respect to saidplate, the frequency of said vibration being a multiple of the frequencyof said rocking movement.

2. The shaving head of claim 1, wherein the rocking axis of said frameand said one longitudinal side of said 5 6 cutter head are located onopposite sides of the longitudi- 3,128,550 4/1964 Miselli 30-43.6 nalcenter plane of the shaving head. 3,156,045 11/1964 Godefroy 3043.33,213,535 10/ 1965- Heyek 3034.1

References Clted FOREIGN PATENTS UNITED STATES PATENTS 5 1,040,41910/1958 Germany. 86, 6/1942 s 103,443 12/1962 Netherlands. ,29 8/1942 Gg 270,913 9/1950 Switzerland. 2,317,177 4/1943 Carissimi 30 43.92 X2,830,364 4/ 1958 Barnard 3043.91 MYRON C. KRUSE, Primary Examiner.

2,920,387 l/1960 Marescalchi 3043.9l 10

